The astronomers found out first, something big was blocking the view to the Orion belt.

All eyes, biological and artificial, were fixed on that black spot. It kept growing.
Several nations build high speed probes, launching them towards the spot while telescopes tried getting a good look at what was out there.
Before any probe could reach the spot, they just vanished. No explosion or static to be received, it was just gone.

More black spots appeared all around our solar system.

Engineers got together quickly and formed a plan to combine all telescopes into one large array and hopefully get a clearer look at the edge of the spots. Entire server farms from the largest search engines and social media sites were converted to process the data coming from every sensor available on the planet.

The results were images from what looked like construction machines expanding the black spots.
A communication probe was hastily set up and launched. It too went silent as it got closer. Any possible form of transmission had been tried to get into contact with whoever was out there.

Feeling like they had no choice, the world leaders launched their most devastating nuclear weapons into space.
Every channel in the world carried the view from the missiles as they headed towards their targets. The edges could barely be seen when the signals stoppped. Each missile had vanished without a trace.

The blackness had almost entirely surrounded our solar system when the message came.

Humanity had been deemed too dangerous to be allowed to mingle with the rest of the galaxy, therefor it had been sentenced to solitary confinement.